Abstract

This paper describes a system of interferometric control as applied to the smaller ruling engine of the Mount Wilson Observatory. The usual mechanism intermittently advances the grating carriage with a spacing closely approximating an integral number of fringes of green Hg198 light. A Michelson interferometer monitors this motion. The interferometer is modulated by deflecting the compensating plate electromagnetically, thus correcting for barometric pressure changes and also causing the fringe pattern to oscillate with a small amplitude at 60 cps. The oscillating fringe pattern is scanned by a phototube and is reproduced on a monitoring cathode-ray tube; any decentering of the nth fringe is detected by synchronous demodulation and is converted to a stored electrical charge. During each spacing operation, a differential correction proportional to the stored error signal is introduced into the mechanism. Corrections average about 1 centifringe (2.5 × 10−7 cm). The system is relatively simple and ensures a very high order of precision in spacing, with extremely straight grooves.

© 1962 Optical Society of America

Full Article  |  PDF Article

References

You do not have subscription access to this journal. Citation lists with outbound citation links are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Cited By

You do not have subscription access to this journal. Cited by links are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Figures (3)

You do not have subscription access to this journal. Figure files are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Tables (1)

You do not have subscription access to this journal. Article tables are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Equations (6)

You do not have subscription access to this journal. Equations are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Metrics

You do not have subscription access to this journal. Article level metrics are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription